Tube sign construction



f Passed Jess 14, 193s UNITED STATES PATENT oFF-ICE mmm l J 'runs stoml consumo-1101s' Simon Sonkin. New York. N. Y., assigner to Samuel C. Miller. New York, N. Y. Y

Original application'september 27. 1988, Serial No. 635.090. Divided and thh application January zz, 1935, Serial No, mi

nomma '(cl. zoo-'1m 10 operation, by reason of failure ofthe insulation used adjacent the contacts holding separable tube elements. In'the large signs comprising separate tubes formed into characters, failure in the insulation at any point very frequently exhibits the lo entire ,sign assembly in an objectionable manner, due to ickering, without any indication as to the point of failure.. thereby consuming considerable time, labor and expense in its repair or renewal to operating conditions. Maintenance of improperly operating units and the conditions referred to is .accompanied by high intensity sparks, particularly adjacent the' electrodes of the tubes, which 'very quickly disrupt these more expensive parts of the sign or the 'essential parts u 'of the assembly to make replacementand repair an expensive item of cost.

It is therefore an object of my invention to provide an electric tubev sign construction; `and in connection with the wiring circuitl for operata@ ing the same, of safety measures which will assure long life and the proper continued operation of the electric sign. assembly or any portion thereof. so that upon failure of the insulation, due tol extraneous elements, erosion. perforation,

, 35 cracking resulting in the breaking down of `the insulation, the' disruptive action of the-short-circuiting resulting from such failure will have the minimum, or substantially no deteriorating effect upon more costly portions of the sign assembly.

an It is therefore contemplated by me to includey in electric tube signs; of the character operating under high potential, and known on the lmarket as neon tube signs, of a safetydevice which will minimise or eliminate any disruptive tendencies g in the operation of the sign, due to failure' in any portion thereof, and to further provide an'installation which will readily indicate the points of failure, should they' occur, so th'at replacement and repair may be facilitated.

.o It is still further contemplated by" me asan object ofmmy invention to provide in an electrical installation such as that usedforoperatingelectric gas tube-signs operating under high potential, of

-a circuit control mechanism which serves to shunt ss thecurrent flowing throughaneleetriesignor portions of the installation operating under faulty conditions, which may be occasioned by failure of insulation, improper adjustment of contacts or imperfection in any portion of the installation, to eliminate the disruptive effect of short 5 circuits through the more fragile or expensive portions of the sign or any element thereof. It

- is contemplated by my inventionto provide in an installation operating under high potential, particularly an electric gaseous tube sign construe` 1o.

tion ofmechanism forming part of the electric circuit, which respondsto the heat generated byl sparking, to minimize or eliminate the disruptivel tendencies of short circuiting, in the more vital parts of such sign installation.- 15

Still further objects of my invention reside' in the provision of an installation for use in connection with electric gas tube signs which, under proper operating conditions of the tube elements, and the lelectrical circuit feeding the same, is 'u inactive,but which upon failure or the development of any defects in the installation, causes i the current to be diverted from the defective part or connection, to avoid damaging of more fragile parts, readily susceptible to damage by high po' u vtential sparks. To attain these objects and s'uch further ob. jectsas may appear hereinI or be hereinafter Apointed out, l2 make reference to the accompanying drawing, forming apart hereof, in whichi 4ll'igure l is a fragmentary-sectional view and diagrammatic wiring installation showing my invention; I

Figure 2in an enlarged detail, partly in iongitudinalscction, of la thermal-responsive spark .gg Bap switch:

Figure 3 is a plan view thereof;

Figure 4 shows rs. fragmentary enlarged detail of another embodiment of my invention in association with a socket installation; I :so

Figure 5 is a fragmentary side elevation o f another embodiment of my invention; y

Figure 61s asection taken onthe of Pill!!! 52 vf f* Figures 'I and 8 illustrate further embodiments A4I of switch elements. L

Making 'reference to the drawing. my invention may be illustrated in connection with an' electric gas tube sign inwhich Il is a sheet. outer plate or panel of a'sisn frame work upon which Il or other representations, in accordance with the JI display to be provided. The electrodes I2 are of standard construction and in the illustration, these preferably have a metallic base I4, in contact with a spring contacting member I5, terminating into a binding post IS, in each socket. The electrodes I2, through the exterior contacting base I4, may be positively connected in the sockets II. Preferably, however, for purposes of effecting best insulating conditions, the contacts I4 are mounted in spaced relationship within the sockets II and are held in this spaced relationship from the walls of the sockets by the standards I'I, connected to the sheet I0 by suitable fastening means I 3. n standards I1 are preferably made of insulating materialA and provided with a tube conforming rider I9, to which the tube is fastened by a twisted wire, as shown at 20. y

For the installation as disclosed, I provide a thermal switch A, shown in detail in Figures 2 and 3, and in my preferred form comprises an Y struction illustrated, a plurality of such tube eieinsulating member 2I, one end of which supports a binding post 22, anchoring in spaced relation to the insulating member 2|, a bi-metallic heat responsive conductor strip 23, rigidly connected to the binding post 22, as by suitable fastening means, such as a screw 24, though spot welding, brazing or simil-ar rigid fastening means may be `employed. The bi-metallic conductor 23 is so positioned that the layer 25 lies innermost and comprises a mtal of low coefllcient of expansion. The outer layer 26 is disposed away from the insulating member 2| and is of a material which has a relatively high coefficient of expansion, when subjected to heat. These two layers 25 and 26, are riveted or otherwise fastened together, in close contact, to avoid any independent action. As the nature and compositions of the separate layers may be varied depending upon operating conditions, these materials may be varied to suit the individual purchaser. I have found that excellent lresults may be obtained by making the layer 25 of invar, a nickel-steel alloy, and the layer 26 of brass.

The end of the insulating member is provided with a combined terminal binding post and set screw 28, carrying at the outer end a tip 29 of spark resisting, electrical contactingV4 material. This is disposed oppositely to the free end of the bi-metallic element 23, which also carries on its inner surface, a small contact point 30 of spark resisting electrical contacting material.

Thermal switch A as provided and illustrated in Figures 2 and 3 may be suitably enclosed in some jacket of glass or otherwise, to keep out dirt or dust particles, and may be so installed in the sign assembly as an independent unit wherever desired of which the following is an illustration.

Referring now to Figure 1, a source of electrical alternating current C, serves to operate through al transformer T, the feed being to the primary circuit thereof. From the secondary circuit S, connected with the terminals 3| and 32, there is provided conductors 33 and 34 connected to the vmost remotely positioned binding posts i6 of the tube elements, and where as in the cononductor c 'to the secondary' The free ends of the ff ."tube elements I3.

With a circuit as just described, the electrical tube elements I3 are connected in series, though it will be readily understood that these elements may be connected in parallel, in accordance with the necessary potential for operating the electric-al gas tubes.

Connected with each pair of terminals I6 of the cooperating electrodes I2, for each of the tube elements, and in parallel with the tube elements, I interpose a thermal switch A, preferably connecting the terminals 22 and 28 by inter,- mediate conductors 31 and 3B. As many thermal switches as desired may be incorporated in the circuit just described, as there are separate tube elements, so that each tube element has an independent shunt circuit in which the thermal switch is interposed.

The thermal switchis adjusted so that the gap between the points 29 and 30 is normally open, at normal Iatmospheric temperatures. 'I'he gap between the points 29 and 3G is so adjusted in relation to the tube element I3, in p arallel therewith, that under normal operating conditions, the resistance across the gap formed by the points 29 and 301s considerably higher than the resistance necessary to properlyoperate the 'I'he gap, however, is so adjusted that the resistance of high potential current across the gap is materially lower than that which may ow through a cracked or impaired insulating socket II, and the most adjacent sec. tion of the panel I0, or in fact, the resistance across the gap 29 and 30 is so adjusted that it is lower than any point of failure where sparking may occur, due to improper mounting, imperfection, snorting caused by moisture, after rain, adjacent the electrodes I2 of the various tube elements.

In operation, any imperfection .adjacent the electrodes, due to failure of the insulation between the electrode I 2 and any part of the supporting mechanism therefor, which would otherwise, on continued operation, cause a flickering in the sign element, and sparking adjacent the electrodes, will have a disruptive effect upon the eectrodes and the insulation. The resistance will therefore be greater than under proper operating conditions. This will result in the current jumping the gap between the contacting points 29 and 30, and the consequent formation of a spark. As a result thereof, the current will flow through the bi-metallic element 23 and the composite strip will be heated. During this action, the movement of the free end of the strip 23 will serve to reduce the spark gap and therefore divert the current through the thermal switch including the conductors 31 and 36, rather than have it flow through the electric tube element I3 and the circuit thereof. As the bi-metallic element 23 lis heated to a greater extent, the contact points 29 and 30 are brought into positive engagement, thereby completely diverting the current through the thermal switch. As the spark is reduced, the temperature of .the bimetallic element 23 diminishes, the spark gap 29 and 30 will again be increased.

It will thus be observed, from the operation of the installation as thus provided., any disruptive tendency through "e delicat rions of the elethe cor especially wi rhicii may s,1ao,ssa e. Y V

be thus disconnected, by the thermal switch, leaving the other elements free to operate in the normal way. Should the conditions tending to cause ashort circuitingI adjacent the electrodes be a temporary one, as by the entrappins oi wa- Q.

ter after rain, upon drying up oi the contact ad- `iacent the electrode, the normal resistance at '.fthis part will. be re-established. and the current ,may again ilow through the tube element, rather than through the thermal switch.

`Should conditions arise which actually permanently impair thel electrical circuit adjacent the electrodes of the tube elements, the intermittent action caused by the variation ofthe spark gap between the contacts II and Il. particularly where a .thermal switch is provided for each tube element as the temperature o! the ibi-metallic element Il varies.' will serve as an. indication for the repair man, to determine which element vxof' the sign assembly requires adjustment. repair or replacement rather than necessitating the in .35 gap until intimate contact is made between the points 2l and 3l, thereby reducing the erosion' eii'ect ofthe spark. f s

Under certain conditions of operation where a single continuous tube element constitutes the sign, I may position across vthe terminals li and I2 of the secondary circuit of the transformer, ,a

thermal switchA, through/the circuit Il, preferably interposing a resistanceelement 4I. This connection" may also optionally be included u wherever thermal switches are used for a plurality of signirelements, and when so used, adds a large safety factor to the entire system generally,

. and 'speciilcally tothe transformer T. f

In the installation previously described, the lthermal switch has been described as connected in shunt or 'parallel with Lthe sign tube elements. I may. however, 'accomplish desirable operating conditions, to sax@ the deteriorating eii'ect of sparks, by connecting a somewhat similar element ss in seriesdwith each of the conductors feeding the electrodes.

. such embodiment f oi ,my invention, reference will not( be made to Figure 4 which shows the electrode end i2 of a.tube element II formed liwithfa contacting base Jl. This is preferably i the,thermal elment control the f For this purpose, as illustrative of Il is'provided with a layer or sheet of heat re- *i sisting conducting material It. 'lhe lower end I4 ofthe coiled element Il terminates in, and is connected to the binding post Il, located in the end of thessocket. The plate ll is held in realiient engagement with the coil ll, by the abutments Il, formed in the walls oi' the socket so that in normal operation, the contacts Il and I8 are held urged against each other, but complete the circuit feeding lthe tube elements.

Bhoiid these become eroded causingthe iormar,

tion of sparks at this point, during operation, the sparking laction`wi1l heat the coil Si, Ihe bi- /metallic material, ,under these condtions, will shift the position of the endo! the coiled element, therebyJresenting a new portion of the contact point Il. 'Ihisoperation will serve to' prevent burning out and wear o! vthe contactingv portions l.' and Il, thereby permitting the use of less expensive alloys for the contacting material, and avoiding rapid deterioration of these elements.

yIn Figure 5I have disclosed another .embodiment of my invention, in which a supporting base minal or binding post Il, iormig part oi.' the electrical circuit. To this terminal there is mounted a bi-metallic strip It, made-oi metals -having widely varying coeilicients of thermal expansion. Ihe free end is biiurcated, and between these iurcate portions there is mounted an insulating block M. This block rides against a loopvl, of the bracket ,against a spring leaf or'latch M. The bracket carries a terminal Il, serving as a means of connecting a conductor forming part of the electrical circuitr The` terminal l! carries a threaded screw 0l, which in l1, made of insulating material, supportant tercontact Il, mounted thereon, in relation to the turn carries a contact point l1. Oppositelyedisposed to the contact point l1, and mounted upon the bi-metallic strip Il, is a contacting point Il. In normal operation, the contacting points i1 and I are held in spaced relationship'. Under conditions wherein sparking'may occur between vthcontacting points l1 and Il, for reasons oc; curring in the 'sign tube construction as previously described, the bi-metallic strip l will' be warped, to urge the contacts" and QI into closer relationship. until final contact is made. In this rposition, the spring member M .will snap beneath lthe block Il, to permanently hold the contacts 61 and .l in engagement-with each other. form /of ^installation may be mounted at some convenient point in the sign assembly, which may be accessible, so that when repair or replacement is made, the operator will merely have to unlatch the spring lea! latch M, and permit the bi-metallic leaf to assume its normal position, with the contacts O1 and il in spaced relation-V ship,and aftery alteration, repair or replacement ntted within a tubular sleeve 4I, lpartially split, vhas been made, the sign assembly is akai'nrin conat l# to make resilient engagement with the base Il. The sleeve Il has a Vpigtail soldered thereto' and connected with a terminal 4l, so rmounted upon a slidable plate ll, held against rotation within a socket made oi insulating material. Forked portions l1 engage VAa rib Il, to hold the plate against rotation, but permitting sliding movement. The terminal has its lower 70 tree end formed with a contact point 40 terminating between the arms of the loop l.. Within thk loop, theres positioned a coiled metal spring llr formed oi' a bi-netallic couple, the` elements whereof have diil'erent thermal coeiiicients of ex- ,ll pansion. The upper end 52 of the coiled lelement Thisin the bil-metallic switches as disposed upon a n relatively iixed point and the metallic strip, rel spectively, for purposes of magnifying the spark gap, the contacting points may bemounted respectively on two'bi-metallic elements operating in opposite directions as shown in Figure 7.

It will further be observed that though I prefer to use the bi-metallic strip for my thermal switch element, other thermally responsive means such as aneroid diaphragm (as shown in Figure 8) may be used with some success and obtain somewhat equivalent operation.

It will thus be observed by the device and installation as described, that electric tube signs.

may be operated with a large measure of safety,

-to avoid the destructive effects of high potential including electrode points normally spaced from each other forming a gap of greater resistance than required for normal operation, such points being mounted upon a member, responsive to current flowing across said gap to urge said electrode points towards each other, said member being free to reassume: the initial position upon discontinuance of said current.

2. For use with a high potential, electrically Operated gas tube sign, a thermal switch comprising electrode contact points mounted in insulated relationship and normally spaced from each other forming a gap of greater resistance than required for normal operation, one of said points being mounted upon a freely movable bimetallic strip responsive to the ow of current across the gap .formed by said points, to urge the points towards each other, said strip being free to reassume the initial position upon discontinuance of said current.

3. For use with a high potential, electrically operated gas tube sign, a thermal switch comprising electrode contact points mounted in insulated relationship and normally spaced from each other, forming a gap of greater resistance than required for normal operation, one of said points being mounted upon a bi-metallic strip responsive to the flow of current across the gap formed by said points, to urge the points towards each other and upon discontinuance of the same being capable of restoring itself to the original position, an insulating member connected adjacent one of said electrodes, and a latch for holding said electrodes in contacting position.

4. For use in a hig'h potential, electrically operated gas tube sign assemblyl a thermal switch comprising connectors mounted in spaced relation and insulated from each other, contact points mounted on said connectors, and an interposed thermally-responsive element for one of said points, operating under sparking conditions across said points, to urge said points in a position having a diminishing electrical resista-nce during flow of high potential current therethrough and formed of material to independently reestablish the original position.

5. For use with a high potential, electricallyoperated gas tube sign, a thermal switch comprising external connectors mountedv upon an insulating member, one of said connectors including a contact point, the other of said connectors comprising a bi-metallic strip holding a second contact point in cooperative lpositionwith said first point, and holding said contact points in spaced relationship, said bi-metallic strip cornprising materials of dissimilar thermal-coefficients of expansion, one of said dissimilar materials of said strip being positionedto urge the bi-metallic strip and the contact carried thereby in closer relationship to the other contact point, under operating conditions increasing said temperature of the bi-metallic strip.

6. A thermal switch of the character described comprising an insulating member having connector terminals, contact points connected with said terminals, one of said points being mounted upon a loi-metallic strip formed of metals of dissimilar thermal coeiiicients of expansion, holding said contact points normally in spaced relationship, forming a spark gap which may be bridged only by high potential current flowing across the gap of the character employed for operating gas tube electric signs, said strip 4being capable of independently re-establishing its original position.

'7. A switch for disconnecting a defective portion of a gas tube sign, comprising a gap circuit connected in parallel with said portion of the sign, said gap circuit including a thermally responsive element for closing the gap upon passage of a high voltage current across said gap to heat said thermally responsive element and independently capable of re-establishing the original gap upon discontinuance ofv said heating effect.

8. A switch of the character and for the purposes described, having a single circuit therethrough including current conducting parts electrically arranged in series with a gap between two `of said parts, one member being a thermal element resiliently responsive to heat to close said gap and upon discontinuance of the heat, independently to open said gap.

9. A switch of the character and for the purposes described, comprising an insulator, terminals connected to said insulator, a circuit contact carried on the insulator at one end' thereof and electrically connected to said terminal, a thermally responsive bi-metallic strip mounted on said insulator and electrically connected to the other terminal, said strip having its free end eX- tending into operative relationship, but normally out of engagement with said contact, said strip being connected in relation to said contact and responding to heat to close the contact and independently tov open said contact upon discontinuance of the heat.

10. A- switch of the character and for the pur- Doses described, including current conducting parts eiectrically'arranged in series ,with a gap between two of said parts, one part being a thermally deformable element resiliently mounted for independently closing or opening said gap upon heating or cooling of said element, respectively.

l1. A switch of the character and for the purposes described and for use in connection with a gas tube sign and varranged for connection across a part of said sign for eliminating the same when defective, said switch including a bimetallic strip in series with a normally open gap formed by said strip and a cooperating contact, said strip being adapted to close said gap due to heat generated in the gap on the continued passage of a high voltage current used in said sign ananas,

and independently capable o! re-establishing it original position.

12. A switch' of the character poses described in connection with a gas tube sign, said switch being connected across at least a'portion of the sign for eliminating said portion when defective, said switch including a bimetallic strip in series with a normally open gap formed by saidstrip and a cooperating contact, said strip being adapted to close said gap due to heat in the. gap on the continuedpassage of a high voltage current used in said sign, said strip being independently urged resiliently to the closed gap or open-gap position.

13. A thermal switch of the character and for they purposes described for use in connection with a gas tube sign, comprising an insulator l .member having connector terminals, a freely eliminating a portion of the gas tube'slgn when defective andindependently serving to resiliently open the gap upon elimination of 'said defective portion. Y v

14. A switch of the character described and for use with la high potential electrically operated gas tube sign for eliminating a defective portion of said sign, comprising terminal portions including an open gap circuit'for connec' tion in parallel with said portion ofthe sign, said gap circuit including a freely movable bimetallic strip for closing the gap and eliminating the defective portion of the sign upon the generation of heat through said strip.

15. A thermal switch for the protection ot ap-l paratus operable by a low current under a high potential, said switch being operable to its closed position by the heat generated by an arc across -the gap formed by its normally spaced contacts and comprising a pair'oi normally spaced oontacts of an arc resisting material and' forming an arc gap therebetween. means carrying one of stripilxed'atoneendandcarryingthesecondl contact at the other endfsaid b ar having its and for the pur-l Rf l metal strip having a low thermal `coeilicient on the side facing said iixed contact and its metal strip'having a high thermal coefliclent on the opposite face, so that an arc across the gapnormally formed by said contacts vwill heat said bar 5 and cause the same to move to close the gap and extinguish the arc and the consequent cooling will cause the bar to'move'to open the, gap, thus returning the switch to its normal condition.

16. A thermal switch for the protection oi ap- 1o paratus operable by a low current under a high r the gap formed by its normally spaced contacts and comprising a pair of normally spaced corn- 15 tacts of an arc resisting material and forming an arc gap therebetween, means carrying one of said contacts and maintaining the same in fixed-` position, and a composite' bimetallic strip xed at'one end `and carrying the second contact at 20 the other end, said bar having its metalstrip having a low thermal coeiilcient on the side facing said-fixed contact and its metal strip having--a high thermal coeillcient on the opposite' face, so that an arc across the gap normally. 25 formed by said contactswill heat said bar and cause the same to move. to close the gap and extinguish the arc andthe consequent cooling will cause lthe bar to move to open the gap, thus returning the switchto its normal condition l'l. A thermal switch for the protection oi apparatus operable by a low current under a high potential, said switch being operable to its closed position by the heat `generated by an arc across the gap formed Vby its normally spaced contacts 35 justing the sise oi' said gap, and a composite bi- 40 metallic vstrip fixed at one end and carrying the second contact at the other end, said bar having its metal strip having a low thermal coeiiicient on the side facing said/ilxed contact and its met'- al strip. having a high thermal coeiiicient on the opposite face, so that an arc across the gap normally formed by said contacts will heat said bar and cause the same to move to close the gap and the arc and the consequent cooling will cause thebar tomove toopen the gli. thus u returningtheswitchtoitsnormslcondition. Y

A SIMON BONKIN. 

